Wednesday, October 28, 2009

Another fine method to exploit SQL Injection and bypass WAF

A method that I discovered today in MySQL documentation struck me with its simplicity and the fact that I haven’t noticed it before. Let me describe this method of bypassing WAF.

MySQL servers allow one to use comments of the following type:

/*!sql-code*/ and /*!12345sql-code*/

As can be noticed, SQL code will be executed from the comment in both cases! The latter construction means that "sql-code" should be executed only if the DBMS version is later than the given value.

As I have been repeatedly asserted [1,2], some WAFs skip comments during signature search. Among such WAFs, there is the latest stable assembly of Mod_Security (v. 2.5.9).

Here is a simple example:

$query = "SELECT name FROM table where id = ".$_GET[id];

$result = mysql_query($query);

Wednesday, October 7, 2009

Password analysis for Windows Live Hotmail users

There’s again news that user account database is available in the Internet. Now it is about Windows Live Mail users. The origin says that more than 10000 passwords of Hotmail user accounts are in public access. I could not miss it, and brief googling leads me to the true origin. Now server operates unstably but google cache works perfectly:)

So, firstly, the list of published and sorted (without repetitions) accounts includes only accounts that start from letters "a" and "b". It means that the full list of users is much bigger than the published list. If we assume that there are about 4000-5000 accounts for every English alphabet letter it’s easy to calculate that the full list of compromised accounts could reach 150000.

Secondly, only 9238 of 10028 published accounts are legitimate. If we also consider Hotmail restriction policy that requires password length to be no less than 6 characters, only 8250 accounts are legitimate.